CRY FREEDOM! ...

CRY FREEDOM! Being a nanny-state lovin' liberal, I'm perfectly pleased with the ban on trans fats. The freedom of fast food joints to inject a cheap, near-poisonous substance into their foods doesn't strike me as a liberty I need worry too much about (I fear this will be another nail in the coffin of liberaltarianism). That said, things like trans fats have always struck me as a sort of market failure. Only X percent of the population knows what they are, only Y percent knows they're bad, and only Z percent would ever think to ask restauranteurs if their foods contains the nasty buggers. And Z is small. So you've got an information asymmetry. That's why, when the FDA forced producers to put trans fats on their labels, they largely disappeared from packaged food. And part of it, too, is a class issue. Studies show a sadly limited percent of the American population can accurately interpret nutrition labels. But since those labels go out to rich and poor alike, producers can't continue exploiting the poor while pacifying the rich. The same, of course, is not true in restaurants.
Restaurants don't have labels. And they're not one size fits, or serves, all. You could force a big sign in each establishment that uses the substances, or a little emblem next to each food that carries the fats, and that would be a perfectly acceptable solution. On the other hand, given that there's no conceivable social good in consumption of the fats, and as Scottpoints out, no conceivable consumer restrictions caused by eliminating them, there's really no sense in simply ensuring that only those without sufficient choices will continue consuming the stuff. Indeed, the ban simply decides that there's no real reason to preserve the freedom of businesses to minimally cut costs by harming the health of their consumers, most of whom won't know they're being damaged till far too late. Indeed, it's the freedom to not be needlessly poisoned so businesses can save a few pennies. And that's a freedom this nanny-stater is willing to protect.
--Ezra Klein